<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title></title>
	<link rel="icon" href="data:,">
	<style>
		.is-loading {
			background: red;
		}
	</style>
</head>
<body>

<div id="root">
	<button 
		:class="{ 'is-loading': isLoading }" @click="toggleClass"
		:disabled="true"
	>Toggle Me</button>
</div>

<script src="bower_components/vue/dist/vue.js"></script>

<script>
	var app = new Vue({
		el: '#root',
		data: {
			isLoading: false,
		},
		methods: {
			toggleClass() {
				this.isLoading = !this.isLoading;
			}
		}
	});
</script>

</body>
</html>